To what extent are fighters conditioning Muscle and Bone? I have been training in SanShou and full contact Taichi through a teacher from taichicentral. We have discussed on some occasions that traditional chinese martial arts taught specific body conditioning exercises to develop sinew, muscle tissue and bone. Bearing in mind some of the gruelling fights that I have witnessed, I wondered if anyone was specifically training in this area.

So I guess the question is how are fighters conditioning the body to accept powerful blows and how can I incorperate this into my training?

You can condition your fist to take more punishment but that should be done gradually over many years. Sparring will toughen up the body gradually as will a variety of sports (my shin can take a lot of punishment due to playing soccer with no shin pads). Hitting something over and over again will of course toughen it to receive more punishment (lightly hitting a rock, punching a post wrapped in straw and hitting a "wooden man" are ways to toughen up the hand). I think medicine balls are also used to toughen the abdominal muscles in boxing by dropping it on the boxer during sit ups (I'm not a boxer).

Had my first AM muay thai fight this weekend and before that I too was kinda worried about bone conditioning, shin pain, etc. Never did anything special other than hit a lot of thai pads, heavy bags, and spar a lot, slowly getting used to the abuse ... and guess what, the adrenaline took care of the rest in the fight, didn't feel a thing. Shins are a little sore the next day, nothing outrageous.

In chinese martial arts, there's an exercise called boning, where you strike forearms with someone. Haven't done those regularly in years. A few weeks ago, a classmate brought them up, so I did a few with him, and I found that I couldn't take as much as I could before. So I'm definitely gonna have to find a way to re-incorporate these into my training again.

There's also a chinese ointment called dit da jow that helps with this, but I think that it's hit or miss, meaning you don't know what type of special brew you gonna get. This local kung fu shop sells it, but the stuff looks so light I wouldn't even touch it!

just go down to your local wal-mart (or whatever cheap store is around) and buy a cheap wooden rolling pin.
Roll you shins everyday, gradually increasing pressure and time. My instructor/senior students told me to do this more (their shins o' steel don't lie). I like to lightly roll my shins before training to deaden the nerves. Kyo doesnt use shinguards, so every little bit helps. Like anything else, it hurts like a b*%^h at first, but I am seeing results.
This also helps to break down the calcium deposits you get over time.
My 2 cents